[Interpreter] Add a simple dead-code elimination bytecode optimizer.

src/interpreter/bytecode-array-builder.cc

Index: src/interpreter/bytecode-array-builder.cc
diff --git a/src/interpreter/bytecode-array-builder.cc b/src/interpreter/bytecode-array-builder.cc
index 5976c6686e51bd92459a8968befa8c2818ceafee..8c9896e5f43c33ed638e6fc99495bf411dad3d70 100644
--- a/src/interpreter/bytecode-array-builder.cc
+++ b/src/interpreter/bytecode-array-builder.cc
@@ -6,6 +6,7 @@
 
 #include "src/compiler.h"
 #include "src/interpreter/bytecode-array-writer.h"
+#include "src/interpreter/bytecode-dead-code-optimizer.h"
 #include "src/interpreter/bytecode-label.h"
 #include "src/interpreter/bytecode-peephole-optimizer.h"
 #include "src/interpreter/bytecode-register-optimizer.h"
@@ -35,6 +36,10 @@ BytecodeArrayBuilder::BytecodeArrayBuilder(Isolate* isolate, Zone* zone,
   DCHECK_GE(context_register_count_, 0);
   DCHECK_GE(local_register_count_, 0);
 
+  if (FLAG_ignition_deadcode) {
+    pipeline_ = new (zone) BytecodeDeadCodeOptimizer(pipeline_);
+  }
+
   if (FLAG_ignition_peephole) {
     pipeline_ = new (zone)
         BytecodePeepholeOptimizer(&constant_array_builder_, pipeline_);